A need exists for an improved surgical instrument to enable safer and more efficacious placement of hand tied knots at remote sites in the body. The use of suture or strings to aid in closing wounds has been known since ancient times. The suture tails left on top of a knot are cut away and removed from the patient in most surgical procedures, since they provide no structural function and are made of a material foreign to the body. With the advent of modern imaging technologies that permit surgical procedures to be conducted through small ports in the patient instead of through large open incisions, the hand tying of knots, sliding loops down the suture and trimming the suture tails at remote surgical sites can be quite challenging. Laparoscopically hand tied knots with conventional knot pushers have surprisingly high failure rates.
Conventional devices for pushing a throw of a knot down to tissue typically consists of a simple shaft with either a hole or a slot at its distal end. The benefits of a hole are that once the one end of the suture is placed through the hole, it cannot fall out while the suture is being passed down toward the wound site. However, under laparoscopic conditions, with gloved hands and bodily fluids on sutures, it is often difficult to pass the suture through a hole, so the holes in the distal end of many knot pushers are made large to facilitate easier suture passage during loading. However, holes that are large enough for unaided easy suture admittance often let the loop of knot slide through the hole while the instrument is being passed down towards the wound closure site. This trapping of the knot loop in the knot pusher hole can at times be problematic and often interrupts the flow of the knot tying procedure. An open slot at the distal end of a knot pusher makes it easier to load the suture (i.e., a hole does not need to threaded) prior to pushing the knot down, but very often the knot loop slips out of the slot and the loop is not adequately pushed down. The loop must be manually reloaded into the distal slot and attempt must again be made to slide the loop down to the wound closure site without it releasing from the slot.
The cutting of surgical suture at remote sites previously required an additional instrument, typically a long shafted scissors. The suture scissors often is introduced through a different port than the standard knot pusher. Use of another instrument for cutting suture thus requires another step, another port, and can be cumbersome and time consuming. To optimize surgical procedure efficacy, such cumbersome and time consuming repeated instrument exchanges should be minimized. Alternative devices are available that offer pre-tied knots either as a single closed loop (i.e. like a noose) or as pre-tied knot with one end of suture attached to a needle. The closed pre-tied (noose) loop does not enable passing the suture through a wound site, but just rather around available freely exposed tissue structures and does not offer a suture cutting option. The pre-tied suturing devices with attached needles, such as Quik-Stitch® (PARE Surgical, Inc., Englewood, Colo.) and Suture Assistant® (Ethicon Endo-Surgery, Inc., Cincinnati, Ohio), can be technically difficult to use, often have questionable knot security and also do not provide for a way of cutting the suture once the needle and its suture are pulled through the suture loop and the knot is tightened.
Instead of needles attached to pre-tied knots, which can be relatively awkward and unreliable, specialized suturing instruments, such as the SEW-RIGHT® SR. 5®. (made by LSI SOLUTIONS, Inc., Victor, N.Y.), may be used to accurately place suture prior to requiring knot tying. Technologies do exist to replace the need for hand tying in the form of the Ti-KNOT® device (by LSI SOLUTIONS, Inc., Victor, N.Y.). Instead of tying a knot by hand, this device crimps a piece of metal, typically titanium, around the sutures to secure them in place. Leaving behind metallic foreign materials is sometimes contraindicated under certain conditions. In the case of inside of the kidney's collecting system, a foreign material, such as titanium, may induce the formation of kidney stones. While such alternative surgical knot pushers exist to aid in remote suturing, they do not combine the features for knot pushing along with an integrated suture cutting mechanism.